Metal blank or billet



I 2, 1930; I PARSQNS ET AL METAL BLANK OR BILLET Original Fi led Jan.'2l, 1928 Fig.2.

Patented Sept. 2, 1930 UNITED STATES PATENT OFFICE CHARLES ALGERNON PARSONS AND EDWARD GARRETT BRO'WNLOW, OF NEWCASTLE- ON-TYNE, ENGLAND; SAID BRO'WNLOW ASSIGNOR TO SAID PARSONS METAL BLANK OR BILLET Original application filed January 21, 1928, Serial No. 248,426. Patent No. 1,729,009, dated September 24, 1929, and in Great Britain February 7, 1927.

Serial No. 359,906.

This application is divided from applica tion, Serial No. 248,426, filed on the 21st of January, 1928, pursuant to which Patent No. 1,729,009 was granted on the 2 lth of Sep- 5 tember, 1929.

The present invention relates to a metal blank or billet for use in the manufacture of metal strip by an extension process such as rolling and is specially applicable to the production of metal strip for turbine blades.

In the particular case of reaction turbine blades formed integral with their roots by a rolling process, the blank or billet has a root-forming portion approximating to the final form and a tail portion to be extended and shaped by rolling to form the strip-like projection constituting the blade proper. It as is usual the blade-for1ningportion of the billet is formed for convenience of rectangular or other simple section, it is found that the blade curves to one side during the rolling process owing to the greater extension of that part of the billet which forms the thinner edge. lVhen strip is rolled in long lengths no particular difiiculty is found in providing guides to keep it straight, but in short lengths and particularly as above where each blade is integral with its root such guiding is practically out of the question.

The main object of the present invention.

is to overcome such difficulties.

With such an object, the present invention consists in the improved blank or billet hereinafter described and having characteristics as defined in the claims appended hereto.

Referring to accompanying drawings which illustrate diagrammatically one form of the invention suitable for the production of reaction turbo-blading:-'

Figure 1 shows in full lines a turbine-blade blank or billet suitable for a cylindrical. rotor and having a curved blade-forming portion, the finished blade being indicated by dotted lines.

Figure 2 being a section on the line 2-2 of Figure 1; while I Figure 3 shows a modified form of blank suitable for a conical rotor.

In carrying the invention into elfect ac- Divided and this application filed May 2, 1929.

is curved as a whole (see the full lines in Figure 1) to that side on which the thinner edge, 6, of the finished blade will be formed.

'Such a curved blank may then be gaprolled in the usual manner, the plane of curvature of the blade-forming portion of the blank lying in what is substantially the common tangent plane of the two gap rolls at about their point of operation.

It the initial curvature of the blank is properly chosen to accord with the degree of cross-sectional nonsymnietry ofthe finished blade,the extra extension of that side of the blade-forming portion which corresponds to the thinner edge, I), of the finished blade will cause the blank to become less curved during each rolling operation and finally to become straight, as shown by the dotted lines in Figure 1.

The blank as described above with a rectangularbase is suitable for cylindrical rotors or stators but the root-forming portion may be modified, for example as shown at a, in Figure 3, to render it suitable for conical rotors and stators or other constructions.

We wish it to be understood that the invention may be applied to forms of metal strip other than turbine blades While the details of the blank or billet described above may be varied to suit particular cases.

Having now described our invention, what we claim as new and desire to secure by Letters Patent is r 1. A metal blank for making straight strips of non-symmetrical cross section, said blank being curved sideways to a degree in accordance with the degree of cross-sectional 1m non-symmetry of the stri to be produced by extension from said blanli 2. A metal blank for the production of turbine blades of non-symmetrical cross section, said blank having a root-forming base and a blade-forming tail integral therewith, said blade-forming tail being curved side- Waysto a degree in accordance with the degree of cross-sectional non-symmetry of the blade to be produced by extension from the blade-forming tail of said blank.

3. A metal blank as claimed in claim 2, in which the root-forming base of the blank is of greater Width than the blade-forming tail.

In testimony whereof We have signed our names to this specification.

CHARLES ALGERNON PARSONS.

EDlVARD GARRETT BROVVNLOV. 

